Rodinal is working at "Beutler" like levels of concentration, so the SO3-- is likely to be more critical.
Next point is obviously as the SO3-- is converted in localised areas to sulphate it will harden the emulsion . . . . . . .
So we have a bit of logic for the three distinct phases of Rodinal that we know of:
1 Primitive what we've just discussed "The Classic Formulae"
2 Middle age - ? & when they switched from Metabisulphite to Sulphite, now we see Antifoggant and Bromide needed possibly for the edge effects - Still made by Calbe
3 Agfa/A&O current Rodinal, less p-Aminophenol, higher pH - 14 more bromide etc
That's my theory anyway